The present invention concerns a pod for producing coffee beverages by infusing ground coffee, in particular beverages of “espresso” type, and a method for producing a beverage from said pod in a pressurized coffee machine.
Priority fields of application of the present invention are those concerning the production of ground coffees and the packaging thereof, and the preparation of coffee beverages from determined quantities of ground coffee(s) packaged in pod form.
A large number of such pods have been described in the literature.
This type of pod is used for producing coffee beverages in pressurized coffee machines, by inserting the pod in an extraction chamber in which said pod is optionally de-compacted before being infused with a hot liquid, hot water in particular, the de-compacting intended to facilitate the passing of the water and the release and solubilizing of coffee aromas to extract said aromas therefrom. De-compacting, before passing the water for extraction, allows the ensured wetting of the entirety of the coffee aggregate to avoid incomplete extraction.
Pods of compacted ground coffee are known which do not have a casing. The non-use of a casing is economically advantageous but translates as crumbling of the matter on the surface of the pod during storage or handling. In addition, when the pod is used in the coffee machine there arise problems of residual deposits of coffee grinds in said extraction chamber, this requiring an additional cleaning operation of the extraction chamber and possibly filters at the output of the liquid from the extraction chamber to prevent risks of proliferating mould, clogging of the output filters of the extraction chamber and risks of ill-functioning and/or of degradation of the coffee machine, or even poor quality of the coffee beverage prepared with the following pod inserted in a non-cleaned extraction chamber.
A description was given in FR 2 879 175 of pods of compacted ground coffee wrapped in a casing, trapping and following the contour of a compacted coffee aggregate, formed of a sheet or film of porous, filtering material and hence permeable. This casing has the advantage of preventing any crumbling of the aggregate of compacted ground coffee before it is inserted in the extraction chamber of the machine, without reducing their breaking or crushing capability under the force of the piston of the coffee machine or preventing the infusion and extraction of coffee aromas to prepare a beverage. However, in this patent, it is sought to promote the exploding of said casing into several fragments inside the extraction chamber of the coffee machine under the pressure of the piston, so as to improve the homogeneity of the infusing and extracting of the components of the ground coffee contained in the pod. For this purpose a woven or non-woven fibre fabric is used of low gram weight, between 15 and 20 g/m2, and preferably having weakened zones of narrower thickness and/or having larger perforations or greater porosity. In practice, in this patent, a food-safe filter paper is used or a casing formed of a film of woven nylon fibres. These casings can therefore be torn, having insufficient elasticity to withstand firstly the deformation resulting from de-compacting and secondly the increase in volume of the pod after it has been moistened for extraction of the coffee aromas via infusion of the pod by means of a hot liquid.
However, this type of pod with filtering casing which can be torn open still has the same disadvantages as the pods without a casing with regard to the need for cleaning the extraction chamber which contains the coffee grinds mixed with fragments of the torn casing of said pod, these having to be evacuated from the extraction chamber towards a storage compartment to allow the preparing of a further beverage in the machine. Since the filter paper or micro-perforated nylon film is not elastically deformable, this material becomes torn giving rise to deposits of coffee grinds in the extraction chamber and on the filters.
A rigid or semi-rigid capsule is known from FR 2 908 970 and WO 2008/071878 that is impervious, capable of being pierced to allow the injection of pressurized water into said capsule through said perforations, and to allow the infusing of the substance, in particular the coffee trapped in said capsule, followed by the collection of an aromatized beverage flowing though said perforations. The packaging casing is initially fully watertight and airtight, and the capsule with its perforated casing containing the residual block of wet coffee grinds is collected after the liquid has flowed through said casing. This type of capsule requires the use of a coffee machine equipped with a needle piercing device and cannot be used in coffee machines not equipped with a device for piercing the casing of the capsule. It is to be pointed out that the needle piercing device is also scarcely hygienic and is likely to clog and become difficult to clean.
Additionally, in patent WO 2008/071878, when the capsule comprises a compacted aggregate of coffee, the piercing device of the casing does not perform de-compacting, the coffee aggregate remaining compact during extraction, which does not allow complete extraction or at least optimal extraction of the coffee aromas when water is injected into said casing.
It is the objective of the present invention to provide a novel type of improved pod with which it is possible to overcome the disadvantages of prior embodiments such as mentioned above.
More particularly, one objective of the invention is to provide a novel type of pod which does not require a specially designed coffee machine to produce a coffee beverage using the sad pod, and which combines the advantageous properties of protecting the coffee aggregate when it is stored and when in use, and which requires simple, easy cleaning of the machine in which the pod is used to produce a coffee beverage.
More particularly, it is one objective of the present invention to provide a “universal” pod of ground coffee i.e. which allows the preparation of coffee beverages using pressurized coffee machines of “fully-automatic” type described in FR 2 879 175.
The present invention more particularly concerns a pod of ground coffee adapted for preparing coffee and coffee beverages using “fully-automatic” machines of the type described in European patent applications EP-A-0 948 927 and EP-A-0 948 926, schematically illustrated in FIGS. 1 and 2 appended to the present application, or in document WO-A-01/91620, and comprising an extraction “group” comprising an infusion chamber into which a quantity of ground coffee is poured then tamped by at least one piston mobile in said infusion chamber, said piston being connected to the water heater of the machine and comprising means for injecting hot water through the ground coffee after it has been tamped in the chamber for extraction of the aromas therefrom.
Another objective of the invention is to provide a pod of ground coffee for machines of the aforementioned type which is able to be produced industrially at low cost.
Finally, a further objective of the invention is to provide a coffee pod which is able to be used in said machines without manual operation by a user to place said pod in position in the machine, and which on the contrary is able to be stored in a reservoir secured to or independent of said machine and inserted automatically from said reservoir into the extraction group of said machine to prepare a coffee, and which is then automatically evacuated after infusion of the coffee contained in said pod.